US2554971A

US2554971A - Sewing machine needle bar operating mechanism

Info

Publication number: US2554971A
Application number: US761916A
Authority: US
Inventors: Adler Solomon
Original assignee: Individual
Current assignee: Individual
Priority date: 1947-07-18
Filing date: 1947-07-18
Publication date: 1951-05-29
Anticipated expiration: 1968-05-29

Description

S. ADLER May 29, 1951 Y SEWING MACHINE NEEDLE BAR OPERATING MECHANISM Filed July 18, 1947 fun INVENTOR. 50107120 Heller WM m HTTO/PNEYS Patented May 29, 1951 SEWING MACHINE NEEDLE BAR OPERATING Q a v MECHANISM 7 Solomon Adler, Gardens, N. Y.

Application July 18, 19,47,Serial No. 761,916

This invention relates to needle bar operating mechanism forsewing machines. This application is a continuation in part of my application for Sewing Machine Needle Bar, filed August 30, 1946, Serial No. 693,918. x g

The conventional type ofsewing machine is provided with an eccentric and a gear mechanism therefor to convert the rotary motion of the main drive shaft into the reciprocating movement through which the needle bar must pass to perform its function in the stitching operation. This kind of mechanism requires a fly wheel of considerable size to equalize the movements of the eccentric. It is, therefore, little suited for a machine ofsmall overall-dimensions, like, for instance, a portable sewing machine.

aoljaims. (o1.112 221) to the frame 1 in order In this latter type of machine a form of needle,

drive is, therefore, desirable which dispenses with the necessity of a crank, eccentric and fiy wheel. Suitably, this can be accomplished by securing to the needle bar a follower pin riding in intersecting grooves of a cylindrical cam member. 1 Thus, when the cam member is rotated a reciprocating movement will be imparted to the needle bar. However, if this form of needle drive is used, difiiculties are liable ,to arise from the limited dimensions of the several co-operating parts and any attempt to provide for a more generous dimensioning of the machine would seriously interfere with the general objects of a compact and portable device. A particular drawback lies in the tendency of the follower pin to become wedged in the intersecting grooves, or to result in excessive friction and wear, or otherwise to endanger the proper engagement with the cam member.

It is an object of the invention to obviate these drawbacks and to provide in general for a needle bar which, in spite of its small dimensions, is reliable in performance, simple in construction and free from heavy or oversized parts.

My invention will be described in the following specification with reference to the drawings, of which:

Fig. 1 is an elevational view of the needle bar, partly in a vertical section;

Fig. 2 is a horizontal section through Fig. 1 on lines 2--2; and

Fig. 3 is a fragmentary view of the follower and its bearing.

Referring to the drawings, it will be seen that the needle bar I is of conventional form and at its lower end carries the needle holder la. The upper end of the bar extends into a flattened shank 3 which is engaged by a bracket 2 secured to prevent the needle bar from rotating. Pivotally connected to the shank 3 is a lever 4 of the thread take-up. All this is well-known in the art and forms nopart of this invention.

According to my invention, a drum or sleeve 5 is rotatably seated in bearings 6 of the frame I. The drum completely encompasses the needle bar and is provided in its inner face with an endless left and righthand thread, generally indicated at 8. A bevel gear 9 is carried at the upper end of the drum for engagement by a mating gear Ill, which latter gear is disposed on the drive shaft (not shown) by which motion is transmitted to the device. For the vertical movement of the needle bar, the drum is apertured, as shown at l l.

Secured to the needle bar is a follower member l2 .which is adapted to ride in the groove of the left and righthand thread of the drum. The stem I3 of the follower extends into an opening M of the needle bar. It is undercut to provide a shoulder l5 and a reduced shank portion Hi. There is thus formed an internal recess H in which a compression coil spring I8 is maintained. The shank l6 protrudes rearwardly from the opening and is restrained against excessive forward displacement by double retaining and adjustment nuts I 9 which are mounted on the threads at the free end of the stem.

The follower thus is adapted both for rotational and translational movement, the latter being in an axial direction.

The contact face 20 of the follower is bowshaped so as to conform to the curvature of the thread groove. As shown in Fig. 2, the contact face has a transversa1 cross-section of considerably greater width than the stem [3. It, thus, is adapted safely to span the gap formed by the intersecting threads.

As indicated at 1|, a clearance adjacent the terminal flange22 of the drum is provided for the purpose of an unobstructed reversal of the follower from one to the other thread at the end of each stroke. Obviously, the upper end of the thread which is not visible in the drawings should be formed in an identical manner.

From the description given it Will be manifest that, when the drum 5 is rotated by means of the drive shaft and intermediate bevel gears 9 and [0, a vertical reciprocating motion is imposed on the needle bar through the follower member. Also, it will be appreciated that the several features embodied in the follower member, to wit, the rotatable seating, the axial movability and the wide contact face, all, contribute in effecting a yielding engagement between follower and thread. In this manner, a smooth sliding fit of the follower in the groove is assured despite the narrow dimensions of the several parts and notwithstanding possible rough surfacing.

Obviously, many modifications are possible without departing from the spirit of the invention. Therefore, except where otherwise limited by the claims,*various alternative structures may be employed.

What I claim is:

1. In a sewing machine, a frame, a needle bar, a cylindrical member encircling a part of said bar, said member being rotatably carried by said frame and having a left and righthand thread, means to impart a revolving action to said memher, the axis of revolution being parallel to -the needle bar, an aperture in said needle bar, a follower member extending through said aperture and being rotatable on its axis and being axially movable, spring means maintained between said follower and saidneedle bar and adapted to urge sai'd follower into contact with said thread, and an operative connection between said follower and said needle bar whereby a reciprocatingmotion' is imparted to the needle bar upon revolution of the cylindrical member.

2. In a sewing machine, a frame, a needle bar, a cylindrical member encircling a part of said bansaid member being rotatably carried by said frame and having a left and righthand thread, means to impart a revolving action to said member, a follower member rotatable on its axis and axially movable, spring means for urging said follower member axially into contact with said thread, the thread terminating at points short of the ends of the cylindrical member in order to permit reversal of direction of the follower at the ends of the strokes, and an operative connection between the follower and the needle bar whereby a reciprocating motion is imparted to the needle bar upon revolution of the said cylindrical member.

3. lPna.=sewingimachine, a needlebar, a cylindrical member'surrounding said needle bar, a frame, bearings in said frame for rotatably carrying the cylindrical member, means to revolve said-cylindrical member about its longitudinal :axis, the cylindrical member having an internal endless left and righthand thread, an elongated followermember secured to the needle bar, the saidmemberbein'g rotatable about an axis perpendicular to the axis of the needle bar and being axially movable, and means for urging said follower towards said internal thread so as to transmit;a-reciproeatingzaction to the needle bar uponrevolution 'ofsaidzfollower member.

SOLOMON ADLER.

REFERENCES CITED The following references are of record in the file-of thispatent:

UNITED STATES PATENTS Number Name Date Re. 19541 Van Dyke Apr. 16, 1935 1,020,057 Ringe 1 Mar. 12, 1912 1,373,764 Rooney Apr. 5, 1921 Garcia Sept. 3, 1942